The first one, valleys. Rivers had to be built over, no one wanted their farms to be turned into a railroad (or at least those with common sense), and deserts had no water and was really hot during the day and cold at night.
World War I and II. These wars caused lots of economic growth and development because there was a pressure to create better inventions. Having better technology could mean the win or lose of a war. :D
fossils, glaciers, and complementary coastlines
Isobars and isotherms are both lines on weather maps that represent patterns of pressure and temperature. They show how temperature and pressure are changing over space. They describe the large-scale weather patterns across a region in the map.
